The invention relates to a motor vehicle with an automated actuator device for a clutch and/or a transmission in the power train. The invention further relates to a method of controlling an actuator device of an automated clutch and/or an automated transmission. The automated clutch and/or automated transmission are collectively referred to as an automated torque-transfer system.
Motor vehicles and actuating devices of the kind that this invention relates to are known from DE 195 04 847, DE 44 26 260, and DE 197 34 023.
In the type of motor vehicles meeting the foregoing description it is of critical importance to reliably detect when the brakes are being applied, because the way in which different control processes are performed depends on the ability to reliably detect an application of the brakes. For example, failing to detect an application of the brakes because of a defective cable or another defective condition, or detecting an application of the brakes when in fact the brakes are not being applied can make the vehicle unsafe or entirely unfit to use, or can lead to dangerous situations.
In view of the foregoing background, the invention therefore has the objective of offering an improvement over the state of the art by providing a motor vehicle with a higher margin of safety or a safety reserve in regard to the correct operation of a control process that depends on whether or not the brakes are applied.
The present invention meets the foregoing objective in a vehicle that has at least one actuator for the clutch and/or the transmission and a control device directing the operation of the actuator through control signals. The vehicle is further equipped with a brake-actuating device such as a pedal or a hand-operated lever. According to the invention, the vehicle has two sensors or switches to monitor the actuation of the brake. Dependent on the signals of one or both of the brake sensors, the control device generates a control signal or control command to the actuator to thereby control the operation of the clutch and/or the transmission.
It is advantageous if the control unit generates a control signal if both brake sensors are signaling an actuation of a brake.
According to a concept of the invention, it can be useful if the control unit generates a control signal if both brake sensors indicate that the brake is not actuated.
It is useful according to the invention, if a control signal is generated in a situation where one of the two brake sensors is signaling an actuation of a brake. In this case, the sensor signal that causes the control signal can come either from the first sensor responding to the brake actuation or the second sensor responding to the brake actuation.
It is also useful, if a control signal is generated in a situation where one of the two brake sensors sends a signal indicating that the brake is not being actuated. In this case, the signal indicating absence of actuation which causes the control signal can come either from the first sensor responding to the absence of actuation or the second sensor responding to the absence of actuation.
A further practical concept of the invention is to use the on- or off-condition of at least one switch to detect an actuation of the brakes and to generate a control signal depending on the condition of the switch.
It is advantageous according to the invention, if the control unit cannot initiate an engine start or send a release signal allowing the engine to be started unless there is signal indicating that the brakes are applied. It can be useful if the engine is allowed to start after the clutch has first been automatically disengaged or if the clutch is already in a disengaged condition. In addition or as an alternative, it can be useful to allow the engine to start only after the transmission has first been automatically shifted into the neutral position or if it is already in the neutral position.
According to a further concept of the invention, it is useful if a crawl movement of the vehicle is allowed only if there is a signal that at least one of the brakes or all of the brakes are in a non-actuated condition. The term xe2x80x9ccrawl movementxe2x80x9d means that the vehicle is moving very slowly without actuating the gas pedal, with the transmission in gear, and with a controlled degree of clutch engagement.
According to a further concept of the invention, it is useful if the control unit generates a signal indicating a locked condition of one or more wheels only if there is a signal indicating a wheel-rpm rate of substantially zero coinciding with a signal indicating that the brakes are applied.
It is advantageous if the correct functioning of the two switches is monitored and if the control unit generates an error signal and starts an emergency program in a case where the switch that should respond first is giving no signal of an actuation, but the second switch is indicating that the brakes are actuated.
It is also particularly useful if the correct functioning of the two switches is monitored and if the control unit generates an error signal and starts an emergency program in a case where the switch that should respond first is indicating an actuation of the brake, but the second switch is giving no signal of an actuation.
The novel features that are considered as characteristic of the invention are set forth in particular in the appended claims. The improved apparatus itself, however, both as to its construction and its mode of operation, together with additional features and advantages thereof, will be best understood upon perusal of the following detailed description of certain presently preferred specific embodiments with reference to the accompanying drawing.